This group studies how organisms sense environmental signals and transduce the signal into changes in gene expression and cell morphology. The group has continued their characterization of the bacterial response to hydrogen peroxide. Two regulators are central to the response to hydrogen peroxide: OxyR, a protein activator that is switched on by oxidation, and OxyS, a novel 107 nucleotide RNA that acts as an activator and repressor of gene expression. The group has defined functional domains within the OxyR protein and elucidated the nature of OxyR-DNA recognition. Active domains within the OxyS RNA and a response element in an OxyS-regulated gene have also been identified. OxyS was found to act at the level of mRNA translation. Using Arabidopsis thaliana as a model system, the group has also initiated a large scale screen for mutants defective in their response to blue light.